JP2009216764A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device, such as a portable terminal, in which outdoor visibility is secured, module strength is improved, and the reduction in the thickness and safety are attained. <P>SOLUTION: The liquid crystal display device includes a liquid crystal layer 14 held in between a first and a second substrates 15 and 16, a lower polarizing plate 17 disposed on the outer side of the first substrate 15, and a protective plate 11, comprising a glass material disposed on the outside of the second substrate 16, and in the liquid crystal device, a scattering preventing sheet 13 commonly used also as an upper polarizing plate is disposed on the outside of the protective plate 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to protection of a display surface of a liquid crystal module.

  In recent years, liquid crystal display devices are frequently used as display devices. In particular, liquid crystal display devices are used as display units for TV receivers, portable terminals, in-vehicle devices and the like because they are thin, lightweight, and save power.

  Among these liquid crystal display devices, particularly in liquid crystal display devices for portable terminals, there are strong demands for securing and improving outdoor visibility, improving the strength of the liquid crystal module, ensuring thinning, and the like due to the usage.

  However, among these demands, for example, there are cases where contradictory demands are demanded for improving the strength and thinning of the liquid crystal module. For example, when the thickness is reduced, it is inevitable that the liquid crystal module component is thinned, and this generally tends to cause a decrease in strength, which goes against improving the strength of the liquid crystal module and ensuring safety.

  Further, in order to ensure and improve outdoor visibility, the occurrence of damage and deterioration with time of the liquid crystal module constituent members is one of the conditions to be avoided. However, the structural members that are resistant to damage and hardly deteriorate with time are generally composed of materials that are difficult to be thinned, and there has been a problem that the above-described requirements cannot be satisfied.

  In addition to these problems, securing safety for portable users is the most important issue due to the usage mode of carrying.

JP-A-9-318932

  The liquid crystal display device disclosed in Patent Document 1 relates to an arrangement for a liquid crystal display panel and a transparent protective plate in relation to an in-car use or the like used for handwriting input or a navigation system.

  FIG. 6 is a schematic cross-sectional view for explaining a conventional liquid crystal display device related to FIG. In FIG. 6, the TFT substrate 62 and the color filter (CF) substrate 63 sandwiching the liquid crystal layer 61 are similar and have a substantially rectangular shape, and the TFT substrate 62 has a mounting portion 621 protruding from the end face of the CF substrate 63. And having a larger size than the CF substrate 63. Further, a lower polarizing plate 64 and an upper polarizing plate 65 are arranged outside the TFT substrate 62 and the CF substrate 63, respectively. A backlight unit 66 composed of a combination of a light source, a light guide plate, a diffusion plate, a lens, and the like is disposed at a position close to the outside of the lower polarizing plate 64, and an upper surface of the mounting portion 621 of the TFT substrate 62. A driver 67 such as a drive circuit is disposed in the circuit. Reference numeral 68 denotes a liquid crystal module.

  On the other hand, a protective plate 70 made of a transparent plate such as a glass plate or an acrylic plate is disposed above the display surface outside the upper polarizing plate 65 with a predetermined space 69 from the liquid crystal module 68. The entire liquid crystal module 68 is covered and the outer peripheral end thereof is held in engagement with the upper case 71. The lower case 72 is disposed so as to surround the backlight unit 66, the liquid crystal module 68, and the like. Further, a black band 73 is formed in a frame shape on the outer peripheral portion of the protective plate 70, and the black band 73 restricts the display area and shields unnecessary portions inside.

  In the liquid crystal display device shown in FIG. 6, the liquid crystal module 68 is covered with a protective plate 70 to protect the liquid crystal module 68 from external impacts.

  With this configuration, it is possible to secure the strength of the liquid crystal module 68 described above to some extent. However, since there is an air space 69 between the upper polarizing plate 65 and the protective plate 70, it is difficult to ensure visibility due to multiple reflection or the like. It becomes. Further, the existence of the space 69 goes against thinning.

  Further, when the protective plate is an acrylic plate, the acrylic plate is easily deformed by an external force, and the external force may damage the liquid crystal module 68 and a part of the liquid crystal module 68. In addition, the acrylic plate tends to be easily damaged mechanically, and deterioration over time cannot be ignored. On the other hand, when using a glass plate, it is superior to an acrylic plate against mechanical damage and deterioration over time, but cracks occur due to impact, etc., and in the worst case, broken glass pieces are scattered. There is a fear, and there is a problem in ensuring the safety of the user.

  As one means for solving such a problem, a configuration has been proposed in which a liquid crystal display panel and a transparent protective plate are disposed in close contact with each other as shown in FIG. This configuration is effective for ensuring visibility.

  However, problems still remain with respect to the damage of liquid crystal modules due to external forces and ensuring the safety of users, and a solution is required.

  The present invention has been made in view of such circumstances, and its purpose is to ensure and improve outdoor visibility, improve the strength of the liquid crystal module, reduce the thickness, and ensure safety in liquid crystal display devices, particularly liquid crystal display devices for portable terminals. An object of the present invention is to provide a liquid crystal display device that can be secured.

  In order to achieve such an object, a liquid crystal display device according to the present invention includes a liquid crystal module and a protective plate made of a glass plate having dimensions to cover the liquid crystal module, and also prevents scattering on the outer surface of the protective plate. It features a configuration in which sheets are arranged.

  According to the present invention, the protective plate and the liquid crystal module are disposed in close contact with each other, and the scattering prevention sheet is disposed on the outer surface of the protective plate, thereby making it possible to ensure visibility, reduce the thickness, and ensure safety. In addition, according to the present invention, the protective plate and the liquid crystal module without the upper polarizing plate are arranged in close contact with each other, and the upper polarizing plate is also arranged on the outer surface of the protective plate to serve as a scattering prevention sheet, thereby ensuring visibility. In addition to further reducing the thickness and ensuring safety, cost reduction can be achieved.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings of the examples.

  FIG. 1 to FIG. 3 are schematic views for explaining an example of a liquid crystal display device according to the present invention. FIG. 1 is a perspective view showing an outline of the overall configuration of a mobile phone according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA of FIG. 1 to 3, a mobile phone 100, which is shown in a perspective view as a whole in FIG. 1, includes a first housing 2 in which a liquid crystal display unit 1 serving as a display surface is disposed, and an operation unit 4 having operation buttons 3. This is a configuration in which the arranged second housing 5 is connected to the hinge portion 6 so as to be foldable.

As shown in FIGS. 2 and 3, the liquid crystal display unit 1 serving as the display surface includes a protective plate 11 made of glass on the display surface side of the liquid crystal module 12, and a scattering prevention sheet on the outer surface 111 of the protective plate 11. 13 is tightly bonded. This scattering prevention sheet 13 has the function of an upper polarizing plate and covers substantially the entire outer surface 111. Details of the configuration of the protective plate 11 will be described later.
On the other hand, the liquid crystal module 12 includes a first substrate (hereinafter referred to as a TFT substrate) 15 and a second substrate (hereinafter referred to as a CF substrate) 16 which are disposed to face each other with a liquid crystal layer 14 interposed therebetween. Is configured to include a lower polarizing plate 17. The TFT substrate 15 and the CF substrate 16 have a substantially similar shape, and have a configuration in which one side of the TFT substrate 15 includes a mounting portion 151 that protrudes from the end surface 161 of the CF substrate 16 by a dimension L1. The lower polarizing plate 17 is formed in an area smaller than the surface area of the TFT substrate 15 to be bonded, and is laminated except for the outer peripheral portion of the substrate. A backlight unit 19 is disposed below the liquid crystal module 12, and a driver 20 such as a drive circuit is mounted on the upper surface of the mounting portion 151 of the TFT substrate 15.

  The CF substrate 16 of the liquid crystal module 12 having such a configuration and the inner surface 112 of the protective plate 11 are bonded with an adhesive 21. This bonding is performed by, for example, a combination of UV light irradiation and heat curing. The protective plate 11 is formed of a glass plate having a shape substantially similar to that of the CF substrate 16. The glass plate has a thickness several times to several tens of times that of the CF substrate 16, and the area is larger than that of the CF substrate. In particular, the mounting portion 151 side of the TFT substrate 15 includes a protruding portion 113 that covers and further extends from the mounting portion 151 and protrudes from the end surface 161 by a dimension L2 (L2> L1). Yes. The protrusion 113 is not joined to either of the substrates 15 and 16 and has a mechanical cantilever structure.

  Further, the frame-like black belt 22 is disposed on the outer peripheral portion of the inner surface 112. Furthermore, as described above, the anti-scattering sheet 13 that also serves as the upper polarizing plate covers and adheres to substantially the entire outer surface 111 including the protrusion 113 of the protective plate 11. Reference numerals 23 and 24 are upper and lower cases.

In Example 1, a protective plate made of a glass plate was placed in close contact with the liquid crystal module via an adhesive, and the outer surface of the protective plate was covered with a scattering prevention sheet that also served as the upper polarizing plate. With this configuration, it is possible to avoid deterioration of the protective plate with time and damage to the surface, thereby improving visibility, module strength, thickness reduction, and safety. In addition, by using the anti-scattering sheet also as the upper polarizing plate, it is possible to ensure improved visibility, thickness reduction, and safety.
Furthermore, by covering the outer surface of the protective plate with a scattering prevention sheet, even if an external force is applied to the protruding portion protruding in a cantilever state from the end face of the CF substrate, the occurrence of cracks can be avoided by the strength of the scattering prevention sheet. Further, even if the protruding portion breaks due to a larger external force, for example, with the end face as a base point, the scattering prevention sheet can prevent the glass pieces from being scattered, and safety can be ensured.
Furthermore, by moving the upper polarizing plate from the joint portion between the protective plate and the liquid crystal module to other places, there are no problems associated with the contact between the upper polarizing plate and the adhesive, and the degree of freedom of member selection can be expanded. .

FIG. 4 is a schematic cross-sectional view for explaining another embodiment of the liquid crystal display device according to the present invention, corresponding to FIG. 3 described above, and the same parts as those shown in FIG. In FIG. 4, the liquid crystal module 12 includes a TFT substrate 15 and a CF substrate 16 which are disposed to face each other with the liquid crystal layer 14 interposed therebetween. Further, a lower polarizing plate 17 and a CF plate 16 are disposed outside the TFT substrate 15 and the CF substrate 16. The upper polarizing plate 18 is provided.
A protective plate 11 made of a glass plate has an anti-scattering sheet 13 tightly bonded to an outer surface 111. The scattering prevention sheet 13 is made of, for example, a transparent acrylic resin member capable of transmitting UV light, and covers substantially the entire outer surface 111. The inner surface 112 of the protective plate 11 is bonded to the upper polarizing plate 18 side of the liquid crystal module 12 via an adhesive 21.

  This joining method will be described in more detail with reference to FIG. FIG. 5 is a schematic cross-sectional view for explaining the manufacturing process of the embodiment 2 shown in FIG. 4, and the same portions as those in the above-mentioned drawings are given the same symbols. As described in the first embodiment, the inner surface 112 and the liquid crystal module 12 are joined by, for example, a combination of UV light irradiation and thermosetting. That is, after the uncured adhesive 21 is disposed and aligned between the liquid crystal module 12 and the protective plate 11, the UV light 75 is irradiated from the outer surface 111 of the protective plate 11 and further heated to cure the adhesive 21. And the protective plate 11 and the liquid crystal module 12 are pressure bonded.

  In this bonding, on the liquid crystal module 12 side, the entire surface of the upper polarizing plate 18 and the entire facing surface including a part of the CF substrate 16 are in the bonding range. In consideration of the difference in properties and the presence of the black band 22, an operation is performed in which the uncured portion of the adhesive does not remain on the joint surface. If an uncured portion remains, for example, there is a risk of discoloration of the polarizing plate due to penetration of the adhesive or a change in the bonding interval at the time of pressure bonding, and reliable curing that avoids them is required.

  In this Example 2, a protective plate made of a glass plate is disposed in close contact with the liquid crystal module via an adhesive, and the outer surface of the protective plate is covered with an anti-scattering sheet. Surface damage can be avoided to improve visibility, module strength, thickness reduction, and safety. In addition, since the outer surface of the protective plate is covered with a scattering prevention sheet, even if an external force is applied to the protruding portion protruding in a cantilevered manner from the end face of the CF substrate, the occurrence of cracks can be avoided due to the strength of the scattering prevention sheet. . Further, even if the protruding portion breaks due to a larger external force, for example, with the end face as a base point, the scattering prevention sheet can prevent the glass pieces from being scattered, and safety can be ensured.

1 is a schematic perspective view showing an outline of an overall configuration of a mobile phone according to an embodiment of a liquid crystal display device according to the present invention. It is a principal part top view of FIG. It is a schematic cross section along the AA line of FIG. It is a schematic cross section explaining another embodiment of the liquid crystal display device according to the present invention. FIG. 5 is a schematic cross-sectional view illustrating a manufacturing process for the liquid crystal display device shown in FIG. 4. It is a schematic cross section explaining a conventional liquid crystal display device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display part, 2 ... 1st housing | casing, 3 ... Operation button, 4 ... Operation part, 5 ... 2nd housing | casing, 11 ... Protection board, 111 ... Outer surface, 112 ... Inner surface, 113 ... Projection, 12 ... Liquid crystal module, 13 ... Anti-scattering sheet, 14 ... Liquid crystal layer, 15 ... First substrate (TFT substrate), 151... Mounting portion, 16... Second substrate (CF substrate), 161... End face, 17. ..Backlight unit, 20 ... driver, 21 ... adhesive, 22 ... black belt, 100 ... mobile phone.

Claims (6)

A flat first substrate, a flat second substrate having a smaller area than the first substrate, a liquid crystal layer sandwiched between the first and second substrates, and the first substrate. A liquid crystal display device having a liquid crystal module comprising a lower polarizing plate disposed outside and an upper polarizing plate disposed outside the second substrate,
A transparent protective plate having a larger area than that of the second substrate is interposed between the upper polarizing plate and the second substrate, and the entire surface of the outer surface of the protective plate is covered with the upper polarizing plate and bonded and bonded together. A liquid crystal display device, wherein a part of the inner surface of a protective plate is closely bonded to the second substrate.   The liquid crystal display device according to claim 1, wherein the protective plate and the upper polarizing plate have a property of transmitting UV light.   The liquid crystal display device according to claim 1, wherein the protective plate is a glass plate. A flat first substrate, a flat second substrate having a smaller area than the first substrate, a liquid crystal layer sandwiched between the first and second substrates, and the first substrate. A liquid crystal display device having a liquid crystal module comprising a lower polarizing plate disposed outside and an upper polarizing plate disposed outside the second substrate,
A transparent protective plate having a larger area than that of the second substrate is disposed outside the upper polarizing plate, and a part of the inner surface of the protective plate is closely bonded to the upper polarizing plate and the outer surface of the protective plate is A liquid crystal display device, characterized in that a scattering prevention sheet made of a transparent resin member capable of transmitting UV light is closely bonded to substantially the entire surface.   The liquid crystal display device according to claim 3, wherein the protective plate and the scattering prevention sheet have a property of transmitting UV light.   The liquid crystal display device according to claim 4, wherein the protective plate is a glass plate.

Images